<template>
  <div class="pagination">
    <button :disabled="pageNo==1" @click="$emit('getPageNo',pageNo-1)">上一页</button>
    <button v-if="startNumAndEndNum[0]>1" @click="$emit('getPageNo',1)">1</button>
    <button v-if="startNumAndEndNum[0]>2">···</button>
    <button v-for="(page, index) in startNumAndEndNum" :key="index" @click="$emit('getPageNo',page)">{{page}}</button>
    <button v-if="startNumAndEndNum[startNumAndEndNum.length-1]<totalPage-1">···</button>
    <button v-if="startNumAndEndNum[startNumAndEndNum.length-1]<totalPage" @click="$emit('getPageNo',totalPage)">{{ totalPage }}</button>
    <button :disabled="pageNo==totalPage" @click="$emit('getPageNo',pageNo+1)">下一页</button>
    <button style="margin-left: 30px">共 {{ total }} 条</button>
  </div>
</template>

<script>
export default {
  name: "Pagination",
  props: ["total", "pageNo", "pageSize", "continues"],
  computed: {
    totalPage() {
      return Math.ceil(this.total / this.pageSize);
    },
    startNumAndEndNum() {
      const { pageNo, totalPage, continues } = this;
      let start = 0,
        end = 0;
      if (continues > totalPage) {
        start = 1;
        end = totalPage;
      } else {
        if (end > totalPage) {
          end = totalPage;
          start = totalPage - continues + 1;
        }
      }
      let arr = [];
      let sum=end-start+1;
      for (let i = 0; i < sum; i++)
        arr[i]=start++
       return arr;
    },
  },
};
</script>

<style lang="less" scoped>
.pagination {
  button {
    margin: 0 5px;
    background-color: #f4f4f5;
    color: #606266;
    outline: none;
    border-radius: 2px;
    padding: 0 4px;
    vertical-align: top;
    display: inline-block;
    font-size: 13px;
    min-width: 35.5px;
    height: 28px;
    line-height: 28px;
    cursor: pointer;
    box-sizing: border-box;
    text-align: center;
    border: 0;

    &[disabled] {
      color: #c0c4cc;
      cursor: not-allowed;
    }

    &.active {
      cursor: not-allowed;
      background-color: #409eff;
      color: #fff;
    }
  }
}
</style>